Image forming apparatus including technique of detecting full state of a waste-toner box

Abstract

A first waste-toner box includes a detection switch wherein a state of the detection switch changes depending on an amount of waste toner stored therein. A second waste-toner box without the detection switch is initially mounted on a housing. The first waste-toner box is mounted after replacement of the second waste-toner box. A sensor circuit detects the state of the detection switch. In a case where the second waste-toner box is mounted on the housing, a controller detects a full state of waste toner stored in the second waste-toner box based on a dot count that is a number of dots forming a toner image formed on a sheet; and in a case where the first waste-toner box is mounted on the housing, the controller detects a full state of waste toner stored in the first waste-toner box based on the state of the detection switch.

What is claimed is: 
     
       1. An image forming apparatus comprising:
 a photosensitive drum; 
 a belt disposed to face the photosensitive drum; 
 a housing configured such that one of a first waste-toner box and a second waste-toner box is selectively mounted thereon, the first waste-toner box including a detection switch wherein a state of the detection switch changes depending on an amount of waste toner stored therein, the second waste-toner box not including the detection switch, the second waste-toner box being initially mounted on the housing, the first waste-toner box being mounted on the housing after replacement of the second waste-toner box; 
 a sensor circuit configured to detect the state of the detection switch; and 
 a controller configured to:
 in a case where the second waste-toner box is mounted on the housing, perform a first full-state detection mode of detecting a full state of waste toner stored in the second waste-toner box based on a dot count that is a number of dots forming a toner image formed on a sheet; and 
 in a case where the first waste-toner box is mounted on the housing, perform a second full-state detection mode of detecting a full state of waste toner stored in the first waste-toner box based on the state of the detection switch detected by the sensor circuit. 
 
 
     
     
       2. The image forming apparatus according to  claim 1 , wherein the detection switch is configured to be switched between a conducting state and a non-conducting state based on an amount of waste toner stored in the first waste-toner box; and
 wherein the controller is configured to, in response to detecting for a first time by the sensor circuit that the detection switch is in the conducting state, shift from the first full-state detection mode to the second full-state detection mode. 
 
     
     
       3. The image forming apparatus according to  claim 1 , wherein the detection switch is configured to:
 be in a conducting state in a case where the waste toner stored in the first waste-toner box is not the full state; and 
 be in a non-conducting state in a case where the waste toner stored in the first waste-toner box is the full state; and 
 wherein the controller is configured to detect the full state of the waste toner stored in the first waste-toner box based on the state of the detection switch detected by the sensor circuit. 
 
     
     
       4. The image forming apparatus according to  claim 1 , wherein the first waste-toner box includes a belt cleaner configured to collect waste toner from the belt. 
     
     
       5. The image forming apparatus according to  claim 1 , wherein the second waste-toner box includes a belt cleaner configured to collect waste toner from the belt. 
     
     
       6. The image forming apparatus according to  claim 1 , wherein, in a case where the second waste-toner box is mounted on the housing, the sensor circuit detects a non-conducting state of the detection switch regardless of an amount of waste toner stored in the second waste-toner box; and
 wherein, in a case where the first waste-toner box is mounted on the housing, the sensor circuit detects:
 a conducting state of the detection switch when the waste toner stored in the first waste-toner box is not the full state; and 
 a non-conducting state of the detection switch when the waste toner stored in the first waste-toner box is the full state. 
 
 
     
     
       7. The image forming apparatus according to  claim 1 , further comprising:
 a first connection terminal connected to ground; 
 a second connection terminal connected to a power supply; 
 wherein the first waste-toner box includes a first detection electrode and a second detection electrode; 
 wherein, in a state where the first waste-toner box is mounted on the housing, the first connection terminal is connected to the first detection electrode and the second connection terminal is connected to the second detection electrode; 
 wherein, when the waste toner stored in the first waste-toner box is not the full state in a state where the first waste-toner box is mounted on the housing, the first detection electrode and the second detection electrode are connected and thus the first connection terminal and the second connection terminal are connected; 
 wherein, when the waste toner stored in the first waste-toner box is the full state in a state where the first waste-toner box is mounted on the housing, the first detection electrode and the second detection electrode are disconnected and thus the first connection terminal and the second connection terminal are disconnected; and 
 wherein, in a state where the second waste-toner box is mounted on the housing, the first connection terminal and the second connection terminal are disconnected regardless of whether the waste toner stored in the second waste-toner box is the full state or not the full state. 
 
     
     
       8. An image forming apparatus comprising:
 a photosensitive drum; 
 a belt disposed to face the photosensitive drum; 
 a housing configured such that one of a first waste-toner box and a second waste-toner box is selectively mounted thereon, the first waste-toner box including detection means wherein a state of the detection means changes depending on an amount of waste toner stored therein, the second waste-toner box not including the detection means, the second waste-toner box being initially mounted on the housing, the first waste-toner box being mounted on the housing after replacement of the second waste-toner box; 
 reading means for reading the state of the detection means; and 
 control means for:
 in a case where the second waste-toner box is mounted on the housing, performing a first full-state detection mode of detecting a full state of waste toner stored in the second waste-toner box based on a dot count that is a number of dots forming a toner image formed on a sheet; and 
 in a case where the first waste-toner box is mounted on the housing, performing a second full-state detection mode of detecting a full state of waste toner stored in the first waste-toner box based on the state of the detection means read by the reading means. 
 
 
     
     
       9. The image forming apparatus according to  claim 8 , wherein the detection means is configured to be switched between a conducting state and a non-conducting state based on an amount of waste toner stored in the first waste-toner box; and
 wherein the control means is configured to, in response to reading for a first time by the reading means that the detection means is in the conducting state, shift from the first full-state detection mode to the second full-state detection mode. 
 
     
     
       10. The image forming apparatus according to  claim 8 , wherein the detection means is configured to:
 be in a conducting state in a case where the waste toner stored in the first waste-toner box is not the full state; and 
 be in a non-conducting state in a case where the waste toner stored in the first waste-toner box is the full state; and 
 wherein the control means is configured to detect the full state of the waste toner stored in the first waste-toner box based on the state of the detection means read by the reading means. 
 
     
     
       11. The image forming apparatus according to  claim 8 , wherein the first waste-toner box includes a belt cleaner configured to collect waste toner from the belt. 
     
     
       12. The image forming apparatus according to  claim 8 , wherein the second waste-toner box includes a belt cleaner configured to collect waste toner from the belt. 
     
     
       13. The image forming apparatus according to  claim 8 , wherein, in a case where the second waste-toner box is mounted on the housing, the reading means reads a non-conducting state of the detection means regardless of an amount of waste toner stored in the second waste-toner box; and
 wherein, in a case where the first waste-toner box is mounted on the housing, the reading means reads:
 a conducting state of the detection means when the waste toner stored in the first waste-toner box is not the full state; and 
 a non-conducting state of the detection means when the waste toner stored in the first waste-toner box is the full state. 
 
 
     
     
       14. The image forming apparatus according to  claim 8 , further comprising:
 a first connection terminal connected to ground; 
 a second connection terminal connected to a power supply; 
 wherein the first waste-toner box includes a first detection electrode and a second detection electrode; 
 wherein, in a state where the first waste-toner box is mounted on the housing, the first connection terminal is connected to the first detection electrode and the second connection terminal is connected to the second detection electrode; 
 wherein, when the waste toner stored in the first waste-toner box is not the full state in a state where the first waste-toner box is mounted on the housing, the first detection electrode and the second detection electrode are connected and thus the first connection terminal and the second connection terminal are connected; 
 wherein, when the waste toner stored in the first waste-toner box is the full state in a state where the first waste-toner box is mounted on the housing, the first detection electrode and the second detection electrode are disconnected and thus the first connection terminal and the second connection terminal are disconnected; and 
 wherein, in a state where the second waste-toner box is mounted on the housing, the first connection terminal and the second connection terminal are disconnected regardless of whether the waste toner stored in the second waste-toner box is the full state or not the full state.